Sonobuoy mooring unit

ABSTRACT

An air-dropped sonobuoy assembly comprising a weighted mooring unit, a submergible buoy carrying hydrophones, and a float with a radio antenna; the mooring unit being separable from the other elements (after reaching a given depth when dropped in the sea) for mooring cable payout and rapid descent to the sea bottom where further cable payout is prevented. At this point a mooring cable-winch in the buoy reels in the cable to lower the buoy to desired operating depth. The specific mooring cable securing mechanism permits rapid payout of cable until the mooring unit bottoms and then quickly locks the cable against further payout so the winch can pull the buoy down to desired depth against the weight of the mooring unit. The mooring unit also contains an auxiliary anchor device which is deployed upon bottoming of the mooring unit.

United States Patent Snyder Nov. 13, 1973 SONOBUOY MOORING UNIT {57]ABSTRACT [75] Inventor: Robert M. Snyder, Jupiter, Fla.

[73] Assignee: The United States of America as An aipdropped sonobuoyassembly comprising a represented the secretary of the weighted mooringunit, a submergible buoy carrying Navy washmgton hydrophones, and afloat with a radio antenna; the 2 Filed; July 2 97 mooring unit beingseparable from the other elements (after reaching a given depth whendropped in the 2 A 2 l 1] 74,551 sea) for mooring cable payout and rapiddescent to the sea bottom where further cable payout is pre- 52 us. (:1.340/2, 102/13 vemed- At this P a mooring: cable-Winch in the [51] Int.Cl. G0ls 1/72 buoy reels in the cable to lower the y to desired [58]Field of Search 9/8, 83; 340/2, Operating depth The specific mooringcable Securing 340/7; 102/13 14, 1Q mechanism permits rapid payout ofcable until the mooring unit bottoms and then quickly locks the cable 5References Cied against further payout so the winch can pull the buoyUNITED STATES PATENTS down to desired depth against the weight of themooring unit. The mooring unit also contains an auxiliary 5:32 3; anchordevice which is deployed upon bottoming of 3:631:550 1/1972 Bullen 9/8 Rthe Primary Examiner-Samuel W. Engle AttorneyR. S. Sciascia et al. 3Claims, 8 Drawing Figures SONOBUOY MOORING UNIT STATEMENT OF GOVERNMENTINTEREST The invention described herein may be manufactured and used byor for the Government of the United States of America for governmentalpurposes without the payment of any royalties thereon or therefor.

BACKGROUND OF THE INVENTION This invention relates generally to thefield of airlaunched moored sonobuoy systems and more specifically to animproved mooring unit for such systems having specific cable lockingfeatures and specific auxiliary anchoring features which are desirableand advantageous.

Many sonobuoy systems are known in the art; however the mooringarrangements disclosed appear to be of complicated impractical designssusceptible to many problems in their production, storage, and use,especially where the systems are to be used in very deep waters. Theprior art mooring systems do not appear to have made suitable provisionfor securing the system in place against storage current forces at greatdepths. With the areas of submarine warfare and submarine detectionincreasing in significance and activity these prior art shortcomings aresignificant and serious.

SUMMARY OF THE INVENTION The shortcomings and deficiencies of the priorart systems and devices have been overcome and the hereinafter-mentionedobjects of the invention have been achieved by an improved air-launchedsonobuoy assembly comprising in combination: a main submersible buoyunit releasably containing an antenna float with a transmitting antennasecured thereto; a weighted non-buoyant mooring unit releasably securedto said buoy unit, said mooring unit provided with a releasableauxiliary anchor device connected thereto by a length of anchor cable,said submersible buoy unit connected to said antenna float by a lengthof cable, and to said mooring unit by a variable length of cable, saidantenna float and said mooring unit constructed and arranged to separatefrom said main submersible buoy unit when a predetermined depth has beenreached after the assembly has been dropped into the sea, said mooringunit comprising structure defining a first chamber for enclosing a coilof mooring cable having one end thereof attached to said submersiblebuoy unit, said structure further defining an outlet passageway for saidfirst chamber to permit payout movement of the mooring cabletherethrough, said mooring unit further comprising a cable braking andlocking means cooperating with said cable and said passageway andmovable between a first position spaced from said cable and saidpassageway and a second position in operative braking engagement withsaid cable and said passageway to stop payout movement of said mooringcable from said chamber through said passageway, drive means urging saidcable braking and locking means towards its second position, a firstlatch mechanism cooperating with said cable braking and locking meansand operative to releasably hold said braking and locking means in saidfirst position, an inertia means cooperating with said latch means andactuatable by impact of said mooring unit against the sea bottom torender said first latch means inoperative to hold said braking andlocking means in its first position and thus to release the braking andlocking means to move to its second position to engage the cable andstop payout of the cable.

STATEMENT OF OBJECTS OF THE INVENTION It is an object of this inventionto provide an improved sonobuoy mooring unit of a simple, rugged, andeffective design which performs well at great depths and underconditions of strong sea currents.

It is a further object of the invention to provide such improved mooringunits which are relatively simple and economical to produce, store, anduse, and which are highly reliable in operation after long storageperiods.

Other objects, advantages, and novel features of the invention willbecome apparent from the following detailed description of the inventionand the claims when considered in conjunction with the accompanyingdrawings wherein:

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a general schematic showingsequentially the stages of deployment of a sonobuoy assembly embodyingfeatures of the invention;

FIG. 2 is a longitudinal cross sectional view through a preferredembodiment of a sonobuoy mooring unit embodying features of thisinvention;

FIG. 3 is a partial longitudinal cross sectional view similar to FIG. 2showing the mooring cable braking means in its cable braking position;

FIG. 4 is a general schematic plan view of the structure shown in FIG. 3to illustrate the manner in which the wraps or turns of the mooringcable are formed around the braking member to complete the braking andcable locking action;

FIG. 5 is a front elevational view of the auxiliary anchor device of themooring unit of the invention shown in FIG. 8;

FIG. 6 is an elevational view of the anchor device shown in FIG. 5looking to the left therein;

FIG. 7 is a plan section view on the line 7-7 of FIG. 8 of the anchordevice; and

FIG. 8 is a vertical sectional view through the anchor device taken online 8-8 of FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1, the sonobuoy assembly1 of the invention, comprising submersible buoy unit 3 and mooring unit2 is shown at the left hand portion of this drawing figure, after beingdropped at the sea surface S. In the next portion of this figure, theassembly components 2 and 3, after reaching a predetermined depth,detach themselves and separate, the weighted mooring until 2 proceedingdownward unwinding a mooring cable 4 from a coil (as described in moredetail hereinafter), carried by mooring unit 2. The mooring cable 4 issecured to an electric motor-powered winch drum (not shown) carried insubmersible buoy unit 3. Proceeding to the right in FIG. 1 the nextsequential stage shows a float 5 connected to buoy unit 3 by cable 7 andcarrying a radio antenna 6 having been. released from buoy unit 3 andmoved upwardly to the sea surface S. In addition, mooring unit 2 hasreached. the sea bottom B at which point the mooring cable is lockedagainst further payout and auxiliary anchor device 8 or AA is deployedfrom the mooring unit. In the right hand view of FIG. 1, the auxiliaryanchor is shown deployed to provide additional holding power to maintainthe position of mooring unit 2 on the sea bottom against the force ofcurrent such as indicated by the arrow. Also at this point the winchdrum (not shown) carried by buoy unit 3 has pulled the buoy unit 3 downto its desired operating depth against the weight of mooring unit 2supplemented by the added drag provided by auxiliary anchor device 8.The sonobuoy assembly is then fully deployed for its conventional andnormal function of detecting targets and transmitting of informationconcerning the same to some control point via antenna 6.

FIG. 2 illustrates a preferred embodiment of the mooring unit of theinvention which contains the coil of mooring cable to-be paid out duringdescent of the mooring unit, the means for braking and stopping cablepayout, and the auxiliary anchor device. The mooring unit comprises ahousing 2 with a cylindrical portion with an open end and an end closedby a hemispherical portion as shown. The open end of the housing 2 isclosed by a transversely extending wall assembly formed by an outerannular ring member 21A which is secured to housing 2 by suitable meanssuch as machine screws as illustrated, an annular plate member 218, andan inner annular ring member 21C all joined together by suitable meanssuch as welded joints as shown. An annular tapered sleeve RS is fittedinside the inner ring member 21C and secured therein by suitable meansnot shown.

The interior space within housing 2 is divided generally into an upperportion C and a lower portion generally hemispherical in shape by atransverse wall assembly formed by brackets 22A welded to housing 2 andannular plate member 22B attached to the brackets by suitable means suchas the machine screws shown. A cylindrical wall member 22C is mounted inthe lower portion of housing 2 with its axis aligned and concentric withthe axis of housing 2, its upper end portion being secured to annularplate 228 as shown by suitable means such as welding and its lower endsecured by similar suitable means to the hemispherical end portion ofhousing 2. Preferably the lower portion of housing 2 surroundingcylindrical wall member 22C is filled with a suitable ballast or weightsuch as cast lead to cause rapid descent of the mooring unit and goodmooring characteristics when the mooring unit is on the sea bottom.

An annular retaining ring member 23 is secured by threaded engagementwith housing 2 and the interior of cylindrical wall member 22C as shown.Retaining ring member-23 supports an annular element 24 formed of asuitable deformable material such as a polystyrene foam. Deformableelement 24 normally supports a thick-walled sleeve or inertia weightmember 25. Positioned inside sleeve or inertia weight member 25 is aretaining cylinder element 26 supported by and secured at its lower endto retaining ring member 23 by suitable means such as welding. A crosspin element 28 is supported by tight frictional engagement indiametrically opposed holes in retaining cylinder26. A movable cablebraking assembly is mounted within the upper portion of retainingcylinder 26 above cross pin element 28, and consists of a tapered ramhead member 29 secured to the upper end of hollow ram shaft 27 bylocking pin 31 as shown, and compression spring 40 acting between upperpin 31 and lower pin 28 to urge ram shaft 27 and its ram head member 29upwardly. The tapered ram head member 29 substantially matches thetapered interior of sleeve RS and is provided with an outercoating orlayer of lead 30. Preferably, both the main portion of ram head member29 and sleeve RS are formed of aluminum.

In normal positions and condition of the mooring unit parts, ram shaft27 and its ram head member 29 are prevented from moving upwardly by thelatching or detent action'of a set of ball elements Bl carried inopenings in retaining cylinder 26 and forced radially in wardly by theinterior surface of inertia weight member or cylinder 25 into engagementwith an annular groove G1 on the exterior surface of ram shaft 27.

An expellable auxiliary anchor device AA is supported internally inretaining cylinder 26 just below retaining pin 28 and consists of thefollowing parts (referring to FIGS. 5-8 in addition to FIG. 2), anannular base member 53 which is attached by two axially extending sidebar elements 54 to a flat cylindrical end element 51. End element 51 isprovided with two projecting lugs 60 and 61 in which is mounted atransverse shaft element 62. Two pivoted anchor fluke members aremounted on either side of side bars 54, each fluke member having theconfiguration of a half (longitudinally divided) hollow cylinder withone end closed as shown best in FIGS. 5-8. The cylindrical walls 52A and52B of the fluke members are provided with transversely extending wallportions A and 70B respectively. Each transversely extending wallportion 70A and 70B is provided with two brackets 56, 57, 58, and 59which are rotatably secured to transverse shaft element 62. A torsionspring 63 is secured at each end thereof to one of the fluke members bysuitable means such as brazing or welding and the spring extends aroundshaft 62 as shown and urges the fluke elements toward the dashed linepositions shown in FIGS. 7 and 8. A length of cable 83 is secured at oneend to cross pin 28 and at the other end to shaft 62 to secure theauxiliary anchor device to the mooring unit assembly.

A compression spring 50 acting between cross pin 28 and end wallportions 70A and 70B of the fluke members urges the auxiliary anchordevice out of retaining cylinder 26 and the mooring unit housing 2. Innormal position of the mooring unit parts, the auxiliary anchor deviceis prevented from being expelled from cylinder 26 and mooring unithousing by the latching or detent action of a set of ball elements B2carried in openings in retaining cylinder 26 and forced radiallyinwardly by the interior surface of inertia weight member or cylinder 25into engagement with an annular groove G2 on the exterior of annularbase element 53 of the auxiliary anchor device AA.

An annular coil of mooring cable 4 is contained within the upper portionC of housing 2 as shown, preferably arranged for cable payout byunwinding from its central interior portion with the cable movingoutwardly through the tapered opening RSO in sleeve member RS anddescribing the path shown by the arrows D and dashed lines of FIG. 2during payout. Payout of the cable 4 occurs after separation of mooringunit 2 from buoy unit 3 during descent of the mooring unit 2 to the seabottom, with the parts of the mooring unit assembly in positions shownin FIG. 2 and the cable moving outwardly through tapered passageway RSOas shown.

When mooring unit 2 strikes the sea bottom, inertia weight member IW,being unrestrained except for the engagement of deformable member 24,continues to move in a downward direction deforming or crushing member24 to the point where the upper end of member 24 clears ball elements B1and groove G1 which releases rarn shaft 27 and ram head member 29 forupward movement into engagement with conical opening R80 and cable 4. Atthis same point enlarged interior poriton A of inertia weight member 25becomes aligned with ball elements B2 and groove G2 which releases theauxiliary anchor device AA for expulsion from housing 2 by spring 50. Asthe auxiliary anchor device moves clear of the cylindrical recess in thehousing 2, the pivoted anchor fluke elements 52A and 52B swing outwardlyunder the urging of spring element 63 into operative sea bottom-engagingpositions to assist in holding the mooring unit in position.

Referring again to upward movement of tapered ram head member 29 intoengagement with tapered opening RSO and cable 4 it will be seen that awedging action occurs which first restrains the outwardly mooring cable4 against the rotating circular motion at the open ing RSO in thedirection shown by the arrows D and then applies a braking force whichat first is insufficient to stop the outward cable movement. Then for abrief period an action accurs, as shown in FIG. 4, in which theoutwardly moving cable passes through a fixed point of engagementbetween members RS and while still undergoing a circular unwindingmotion at the inside portion of the annular coil in the upper portion ofhousing 2. The force continuing outward cable movement is caused by thebuoyancy of unit 3 and/or sea current forces. Since the point at whichthe cable is engaged by members RS and 3 is fixed or moving relativelyslowly as compared with the rate of unwinding at the inner portion ofthe annular coil, the cable beneath the ram head 29 wraps itself aboutram shaft member 27 in a series of turns, as illustrated in FIGS. 3 and4, to the point at which the frictional drag increases, pulls ram head29 up into sufficiently tight engagement with member RS and the cable 4to positively stop and lock cable 4 against further outward movement.For very strong forces tending to pull the cable out through the pointof engagement between members 29 and RS, a second layer of overlappingcable wraps may be required and will inherently be formed on shaft 27which advantageously provides greatly increased drag or snubbing action.

As previously mentioned, secure locking of the cable 4 against outwardmovement then not only provides secure mooring of unit 3 but permits thewinch drum in buoy unit 3 to pull unit 3 down to desired operating depthagainst the weight and drag of mooring unit 2 and anchor device AA. Thiswinch feature is not described in detail since it forms no part of thepresent invention.

It is believed clear from the above description and discussion thatapplicant has provided an improved mooring unit for a sonobuoy assemblyin accordance with the objects of the invention.

What is claimed is:

1. An improved air-launched sonobuoy assembly comprising in combination:

a main submersible buoy unit releasably containing an antenna float witha transmitting antenna secured thereto;

a weighted non-buoyant mooring unit releasably secured to said buoyunit, said mooring unit provided with a releasable auxiliary anchordevice connected thereto by a length of anchor cable, said submersiblebuoy unit connected to said antenna float by a length of cable, and tosaid mooring unit by a variable length of cable, said antenna float andsaid mooring unit constructed and arranged to separate from said mainsubmersible buoy unit when a predetermined depth has been reached afterthe assembly has been dropped int-o the sea, said mooring unitcomprising structure defining a first chamber for enclosing a coil ofmooring cable having one end thereof attached to said submersible buoyunit, said structure further defining an outlet passageway for saidfirst chamber to permit payout movement of the mooring cabletherethrough, said mooring unit further comprising a cable braking andlocking means cooperating with said cable and said passageway andmovable between a first position spaced from said cable and saidpassageway and a second position in operative braking engagement withsaid cable and said passageway to stop payout movement of said mooringcable from said chamber through said passageway, drive means urging saidcable braking and locking means towards its second position, a firstlatch mechanism cooperating with said cable braking and locking meansand operative to releasably hold said braking and locking means in saidfirst position, an inertia means cooperating with said latch means andactuatable by impact of said mooring unit against the sea bottom torender said first latch means inoperative to hold said braking andlocking means in its first position and thus to release the braking andlocking means to move to its second position to engage the cable andstop payout of the cable.

2. The improved assembly of claim 1 in which said mooring unit furthercomprises:

structure defining a second chamber, said chamber constructed andarranged to releasably contain said auxiliary anchor device connected bya cable to said structure, expelling means cooperating with said anchordevice for moving said anchor device out of said second chamber intooperative anchoring position outside said chamber, a second latchmechanism cooperating with said expelling means to maintain saidexpelling means in inoperative condition and prevent movement of saidanchor device from said second chamber, said inertia means cooperatingwith said second latch mechanism to render said expelling meansoperative to expel the anchor device from said second chamber uponimpact of said mooring unit against the sea bottom.

3. The improved assembly of claim 2 in which said means urging saidbraking and locking element toward its second position, and saidexpelling means comprise spring devices.

1. An improved air-launched sonobuoy assembly comprising in combination:a main submersible buoy unit releasably containing an antenna float witha transmitting antenna secured thereto; a weighted non-buoyant mooringunit releasably secured to said buoy unit, said mooring unit providedwith a releasable auxiliary anchor device connected thereto by a lengthof anchor cable, said submersible buoy unit connected to said antennafloat by a length of cable, and to said mooring unit by a variablelength of cable, said antenna float and said mooring unit constructedand arranged to separate from said main submersible buoy unit when apredetermined depth has been reached after the assembly has been droppedinto the sea, said mooring unit comprising structure defining a firstchamber for enclosing a coil of mooring cable having one end thereofattached to said submersible buoy unit, said structure further definingan outlet passageway for said first chamber to permit payout movement ofthe mooring cable therethrough, said mooring unit further comprising acable braking and locking means cooperating with said cable and saidpassageway and movable between a first position spaced from said cableand said passageway and a second position in operative brakingengagement with said cable and said passageway to stop payout movementof said mooring cable from said chamber through said passageway, drivemeans urging said cable braking and locking means towards its secondposition, a first latch mechanism cooperating with said cable brakingand locking means and operative to releasably hold said braking andlocking means in said first position, an inertia means cooperating withsaid latch means and actuatable by impact of said mooring unit againstthe sea bottom to render said first latch means inoperative to hold saidbraking and locking means in its first position and thus to release thebraking and locking means to move to its second position to engage thecable and stop payout of the cable.
 2. The improved assembly of claim 1in which said mooring unit further comprises: structure defining asecond chamber, said chamber constructed and arranged to releasablycontain said auxiliary anchor device connected by a cable to saidstructure, expelling means cooperating with said anchor device formoving Said anchor device out of said second chamber into operativeanchoring position outside said chamber, a second latch mechanismcooperating with said expelling means to maintain said expelling meansin inoperative condition and prevent movement of said anchor device fromsaid second chamber, said inertia means cooperating with said secondlatch mechanism to render said expelling means operative to expel theanchor device from said second chamber upon impact of said mooring unitagainst the sea bottom.
 3. The improved assembly of claim 2 in whichsaid means urging said braking and locking element toward its secondposition, and said expelling means comprise spring devices.